Manual Reset High Temperature Limit Test; Gas Pressure Switch Tests; Low Gas Pressure Switch; High Gas Pressure Switch - Harsco Industrial SC-1500 Owner's Manual

3.10.3 Manual Reset High Temperature Limit Test

The boiler is furnished with a manual reset high temperature limit which features a probe installed near the
boiler's outlet in order to measure the outgoing supply water temperature. This probe is connected to the
manual reset high temperature limit by a thin, metal capillary tube. The manual reset high temperature limit is
located inside the boiler's front door, toward the top of the control panel and is identified with a yellow label.
Test the manual reset high temperature limit control as follows:
1. Cycle the boiler on by generating a heat request.
2. Allow the boiler to proceed through ignition until main flame is established.
3. Using a flathead screwdriver, turn down the setting on the manual reset high temperature limit to its
lowest value. Turning the screwdriver counter-clockwise decreases the temperature setting.
4. When the outgoing supply water temperature exceeds the setting on the manual reset high
temperature limit, the main burner will shut off.
The NURO touchscreen will display 10009: "High Temperature Limit". Return the system to normal
operation by readjusting the setting on the manual reset high temperature limit to its default setting, press the
reset button on the manual reset high temperature limit, and finally touch any prompts from the NURO
control.

3.10.4 Gas Pressure Switch Tests

3.10.4.1 Low Gas Pressure Switch

The boiler is furnished with a low gas pressure switch, installed near the boiler's main gas shutoff/control
valve. The operation of this switch must be checked as follows:
1. Cycle the boiler on by generating a heat request.
2. Allow the boiler to proceed through ignition until main flame is established.
3. Slowly close the main gas cock while the burner is operating.
4. When the available gas pressure drops below the setting of the low gas pressure switch, the main
burner will shut off.
When the low gas pressure switch opens, the NURO touchscreen will display 10012: "Low Gas Limit". Even
after re-opening the main gas cock, 10012: "Low Gas Limit" will remain on until the NURO display until the
boiler is manually reset.

3.10.4.2 High Gas Pressure Switch

The boiler is furnished with a high gas pressure switch, installed near the boiler's main gas shutoff/control
valve. The operation of this switch must be checked as follows:
1. Before starting the boiler, close the downstream gas cock located inside the boiler's enclosure.
2. Cycle the boiler on by generating a heat request.
3. Allow the boiler to proceed to ignition.
4. When gas pressure exceeds the setting of the high gas pressure switch, the main burner will shut off.
When the high gas pressure switch opens, the NURO touchscreen will display 10011: "High Gas Limit".
Even after re-opening the downstream gas cock inside the boiler, 10011: "High Gas Limit" will remain on
the NURO display until the boiler is manually reset.
TM
P-K SONIC Gas Fired Boiler
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